BU-410: Charging at High and Low Temperatures

Learn how to extend battery life by moderating ambient temperatures.

Batteries operate over a wide temperature range, but this does not give permission to also charge them at these conditions. The charging process is more delicate than discharging and special care must be taken. Extreme cold and high heat reduce charge acceptance, so the battery must be brought to a moderate temperature before charging.

Older battery technologies, such as lead acid and NiCd, have higher charging tolerances than newer systems. This allows them to charge below freezing but at a reduced charge C-rate. When it comes to cold-charging NiCd is hardier than NiMH.

Table 1 summarizes the permissible charge and discharge temperatures of common rechargeable batteries. The table excludes specialty batteries that are designed to charge outside these parameters.

Battery type

Charge temperature

Discharge temperature

Charge advisory

Lead acid

–20°C to 50°C
(–4°F to 122°F)

–20°C to 50°C
(–4°F to 122°F)

Charge at 0.3C or lessbelow freezing.
Lower V-threshold by 3mV/°C when hot.

NiCd, NiMH

0°C to 45°C
(32°F to 113°F)

–20°C to 65°C
(–4°F to 149°F)

Charge at 0.1C between –18°C and 0°C.

Charge at 0.3C between 0°C and 5°C.
Charge acceptance at 45°C is 70%. Charge acceptance at 60°C is 45%.

Li-ion

0°C to 45°C
(32°F to 113°F)

–20°C to 60°C
(–4°F to 140°F)

No charge permitted below freezing.
Good charge/discharge performance at higher temperature but shorter life.

Table 1: Permissible temperature limits for various batteries.Batteries can be discharged over a large temperature range, but the charge temperature is limited. For best results, charge between 10°C and 30°C (50°F and 86°F). Lower the charge current when cold.

Low-temperature Charge

Fast charging of most batteries is limited to 5°C to 45°C (41°F to 113°F); for best results consider narrowing the temperature bandwidth to between 10°C and 30°C (50°F and 86°F) as the ability to recombine oxygen and hydrogen diminishes when charging nickel-based batteries below 5°C (41°F). If charged too quickly, pressure builds up in the cell that can lead to venting. Reduce the charge current of all nickel-based batteries to 0.1C when charging below freezing.

Nickel-based chargers with NDV full-charge detection offer some protection when fast charging at low temperatures; the poor charge acceptance when cold mimics a fully charged battery. This is in part caused by a high pressure buildup due to the reduced ability to recombine gases at low temperature. Pressure rise and a voltage drop at full charge appear synonymous.

To enable fast charging at all temperatures, some industrial batteries add a thermal blanket that heats the battery to an acceptable temperature; other chargers adjust the charge rate to prevailing temperatures. Consumer chargers do not have these provisions and the end user is advised to only charge at room temperature.

Lead acid is reasonably forgiving when it comes to temperature extremes, as the starter batteries in our cars reveal. Part of this tolerance is credited to their sluggish behavior. The recommended charge rate at low temperature is 0.3C, which is almost identical to normal conditions. At a comfortable temperature of 20°C (68°F), gassing starts at charge voltage of 2.415V/cell. When going to –20°C (0°F), the gassing threshold rises to 2.97V/cell.

Freezing a lead acid battery leads to permanent damage. Always keep the batteries fully charged because in the discharged state the electrolyte becomes more water-like and freezes earlier than when fully charged. According to BCI, a specific gravity of 1.15 has a freezing temperature of –15°C (5°F). This compares to –55°C (–67°F) for a specific gravity of 1.265 with a fully charged starter battery. Flooded lead acid batteries tend to crack the case and cause leakage if frozen; sealed lead acid packs lose potency and only deliver a few cycles before they fade and need replacement.

Li ion batteries offer reasonably good charging performance at cooler temperatures and allow fast-charging in a temperature bandwidth of 5 to 45°C (41 to 113°F). Below 5°C, the charge current should be reduced, and no charging is permitted at freezing temperatures. During charge, the internal cell resistance causes a slight temperature rise that compensates for some of the cold. The internal resistance of all batteries rises when cold.

Many battery users are unaware that consumer-grade lithium-ion batteries cannot be charged below 0°C (32°F). Although the pack appears to be charging normally, plating of metallic lithium can occur on the anode during a sub-freezing charge. This is permanent and cannot be removed with cycling. Batteries with lithium plating are more vulnerable to failure if exposed to vibration or other stressful conditions. Advanced chargers (Cadex) prevent charging Li-ion below freezing.

Advancements are being made to charge Li-ion below freezing temperatures. Charging is indeed possible with most lithium-ion cells but only at very low currents. According to research papers, the allowable charge rate at –30°C (–22°F) is 0.02C. At this low current, the charge time would stretch to over 50 hours, a time that is deemed impractical. There are, however, specialty Li-ions that can charge down to –10°C (14°F) at a reduced rate.

High-temperature Charge

Heat is the worst enemy of batteries, including lead acid. Adding temperature compensation on a lead acid charger to adjust for temperature variations is said to prolong battery life by up to 15 percent. The recommended compensation is a 3mV drop per cell for every degree Celsius rise in temperature. If the float voltage is set to 2.30V/cell at 25°C (77°F), the voltage should read 2.27V/cell at 35°C (95°F). Going colder, the voltage should be 2.33V/cell at 15°C (59°F). These 10°C adjustments represent 30mV change.

Table 2 indicates the optimal peak voltage at various temperatures when charging lead acid batteries. The table also includes the recommended float voltage while in standby mode.

Charging nickel-based batteries at high temperatures lowers oxygen generation, which reduces charge acceptance. Heat fools the charger into thinking that the battery is fully charged when it’s not.

Charging nickel-based batteries when warm lowers oxygen generation that reduces charge acceptance. Heat fools the charger into thinking that the battery is fully charged when it’s not. Figure 3 shows a strong decrease in charge efficiency from the “100 percent efficiency line” when dwelling above 30°C (86°F). At 45°C (113°F), the battery can only accept 70 percent of its full capacity; at 60°C (140°F) the charge acceptance is reduced to 45 percent. NDV for full-charge detection becomes unreliable at higher temperatures, and temperature sensing is essential for backup.

Lithium-ion performs well at elevated temperatures but prolonged exposure to heat reduces longevity. Some lithium-based packs are momentarily heated to high temperatures. This applies to batteries in surgical tools that are sterilized at 137°C (280°F) for up to 20 minutes as part of autoclaving. Oil and gas drilling as part of fracking also exposes the battery to high temperatures.

Capacity loss at elevated temperature is in direct relationship with state-of-charge (SoC). Figure 4 illustrates the effect of Li-cobalt (LiCoO2) that is first cycled at room temperature (RT) and then heated to 130°C (266°F) for 90 minutes and cycled at 20, 50 and 100 percent SoC. There is no noticeable capacity loss at room temperature. At 130°C with a 20 percent SoC, a slight capacity loss is visible over 10 cycles. This loss is higher with a 50 percent SoC and shows a devastating effect when cycled at full charge.

Figure 4: Capacity loss at room temperature (RT) and 130°C for 90 minutes
Sterilization of batteries for surgical power tools should be done at low SoC.

Test: LiCoO2/Graphite cells were exposed to 130°C for 90 min.at different SoC between each cycle.Source: Greatbatch Medical

Caution:

In case of rupture, leaking electrolyte or any other cause of exposure to the electrolyte, flush with water immediately. If eye exposure occurs, flush with water for 15 minutes and consult a physician immediately.

Last updated 2016-04-02

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Batteries in a Portable World

Comments

On January 12, 2011 at 11:02pm

Girish.K wrote:

How to calculate the connected load of battery chargers
360V-150A-80% efficency

On August 24, 2011 at 10:33am

Janusz Konopka wrote:

Battery means several cells connected in series. I the course of work (after several charging and discharging cycles) one may note important differences between particular cells. Despite of monitoring particular cells during discharge it chappens that battery become useless because e.g. one cell is much weaker. I founfd it in the case of my electric bike. After, say, some 30 cycles battery become usless. When I performed separate charging of weaker cells the baterry recovered and could be used again.
Plese give me the approximate internal resistance of Li-Ion cell (dV/dI). This parameter will may be decisive in controlling quality of each cell.

On October 31, 2011 at 7:48am

Max Dirnberger wrote:

Dear Janusz,

This will be because your charger is not doing charge balancing. When Li-Ion batteries are in series (most battery packs) this step is often not implemented but must be to avoid the problem you mention

On December 24, 2011 at 9:03pm

Omair wrote:

So basically, if I don’t requite the batteries to fast charge, and since I plug my phone to the charger before bed, I actually prefer it to charge slowly in order to reduce stress, wouldnt cooling the phone to about 15°every night
help elongate my battery life? (Accodibg to your other post, by uptill 15%).
The battery in consideration is a 3.7v 1230mAh Li-ion battery.

On March 13, 2012 at 7:23pm

Happy wrote:

So i have already read all the lesson above. my question is which one is the best metode, charging at the lowest or highest temperature for range 10 - 30C that you mentioned?

thanks for the answer

On June 24, 2012 at 6:45pm

jo wrote:

Hi

On July 20, 2012 at 3:48am

emad wrote:

I connect my phone to my pc ( tethering to get internet ) about 4 to 5 times last weak and i found that my battery is get fully charge after 2hours connecting to the charger instead of 2h 30min as usual .Is that mean that my battery health is affected too much?
and usualy i connect my charger when my battery charge about 25% : 40%
is it okay , or better to leave it to fully discharge befor charge it agail??
please help
my battery is li-ion 1200
the room temp. about 28° : 30°c

On September 30, 2012 at 11:25am

Garry wrote:

So i have already read all the lesson above. my ­question is which one is the best metode, charging at the lowest or highest temperature for range 10 - 30C that you mentioned?

On December 17, 2012 at 8:29am

Dave Dutton wrote:

I have heard lately from Makita salesman that charging warm is best. How warm? I don’t know. I am thinking that since the Lipos like to discharge at near 100 degrees F that charging might be best near that temperature, too.
Anyone with data? Anywhere? I am studying.

On January 14, 2013 at 2:27pm

Pim wrote:

Can I charge a Li-ion above 40C till 50C? With a voltage of 3,92Volt (50%) without damage the battery?

On May 8, 2013 at 8:43pm

Stephen wrote:

Compare to other type of battery, NiCd gives best performance in charging for temperature over 40 degree C.
High Temp NiCd can doing good at 70 degree C. That is why they still use in Emergency Lighting application.
I can also make Low Temp NiCd which perform 65% at -20 degree C. It is heard that some companies can even supply NiCd work at -40 degree C.
My experience is that, Li-ion battery become unstable when over 40 degree C. It could be dangerous of fire if you get products from unprofessional manufacturer.
0 - 40 degree C is the suitable range for most Li-ion.

On May 29, 2013 at 1:33am

praveen wrote:

can anybody tell me how to calculate battery sizing when the load power is 12KW

On June 29, 2013 at 11:52pm

GILBERT M. SAMOITA wrote:

Hi,
I have been a keen follower of your site and i have interests i battery manufacturing. Please advise me on factors influencing charge acceptance.

On September 5, 2013 at 5:24pm

dale wrote:

hi i was wondering about batteries will they be a bomb if you put too much heat on it

On September 18, 2013 at 2:03am

Tom Wald wrote:

Wireless chargers for cellphones increase battery temperature. The third party fonesalesman brand QI charger for my Samsung Galaxy S4 takes the battery temperature up to around 37 degrees, maybe a little more for long charges, whereas charging by plugging it in produces a very small temperature rise.

Are there any safety concerns here? Will the battery life be significantly degraded?

On December 15, 2013 at 4:35pm

Oto wrote:

What about alkaline rechargable batteries and NiZn? What are temperature limits for charging?

On December 17, 2013 at 6:31am

stephen wrote:

Special NiCd battery can be charged at temp up to 70°C, this is so called High Temp NiCd, normally used in maintained Emergency Lighting in Europe regulation, especially in UK.
They are in floating charging all the time, and must be over 70% capacity after working in four years.
Another special Low Temp NiCd can work down to -40°C. This is used mostly in cold storage warehouse.
Anyone want to know more can contact me.

On December 18, 2013 at 1:29am

praveen wrote:

@Stephen you have mentioned they are in float charging all the time, so what would be tha max cahrge and discharge rates it can be operated?

On December 24, 2013 at 11:15pm

muhammadmutlab wrote:

q786 low battre tam

On February 14, 2014 at 6:36am

William wrote:

I have a lithium battery in my laptop, I lost my dell charger and have a rocket fish charger which allows my computer to run but it has 0% charge. If my plug is pulled out of the outlet the computer shuts off.

Would putting my battery in the freezer for a couple days be a good idea, pointless, or a terrible idea? A friend told me it can bring back some battery life that has been slowly degrading, is this true?

On June 24, 2014 at 8:36am

Chris Fox wrote:

I have a small solar cell charging two Lithium batteries in series that run a very low power device in an industrial application. The device will normally run a year on four “AA” alkaline cells, so it’s power consumption is very low. The power from the small solar cells is also very small current. What I need is to keep the system running indefinitely with daily sunlight. Can I let the solar cell charge the lithium battery constantly (when there’s light) through a resistance to minimize the current? Because of the very low currents involved, I think the charging current could be microamperes. Would that damage the lithium cells?

On August 29, 2014 at 10:14pm

Ankitha Jayan wrote:

I have a new smartphone, it has a “Li-Ion 2000 mAh battery”. Should i need to fully charge it before first use…??? Am used my phone while i charging first time . Is there any problem with this…? How can i get maximum life time

On October 18, 2014 at 8:41am

Brian W wrote:

I have a question with regards to the solar charger temperature limits as opposed to the battery temperature limits itself - I’m I’m out camping, say, in the winter, and need to charge my smartphone, as long as I kept the phone/battery w/in its recommended temperature range, would it not matter how cold the solar charger is?

On January 1, 2015 at 1:32am

wajahat wrote:

hi
any softwear who charged the laptop in cold weathr witout electrictcity?

On January 15, 2015 at 11:22pm

BOORA wrote:

I have learnt so much about Li-ion batteries. But thow can we measure/calculate the battery backup after 50% use, If i used the battery with 100%,60% 30% discharge levels.Kindly explain more about this.

On May 17, 2015 at 7:12pm

raju wrote:

What should be the max temperature of electrolyte

On January 19, 2016 at 7:49am

holy wrote:

What is maximum charge of a car battery?

On March 24, 2016 at 1:30am

jheandianesanjuan wrote:

What if I do if when I pku my phone.. it shuts off and when I charged it in the outlet.. it just 0%all day long..

On March 24, 2016 at 1:32am

jheandianesanjuan wrote:

Plus help me how to use my cellphone because when I plug it in the outlet it shuts down.. and when I charged it off it s just0%all day long???what will I do.. pls hep le

On June 27, 2016 at 5:47pm

Zsean wrote:

I am making a device which uses a dc heater with a builtin battery the heater runs from battery and the heater and the battery is adjacent to eachother the heat produced will damage the battery how can i prevent the battery from damaging….

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